Burning solids fuel suspended as an emulsion makes practical sense. Solid fuel like coal is much cheaper per BTU [British thermal unit] than liquid fuel like oil. A barrel of oil has approximately 6.6 gigajoules of heat and costs approximately 110 dollars meaning oil costs approximately 16 dollars per gigajoules of heat. Methanol costs approximately 17 dollars per gigajoule and ethanol approximately 17-20 dollars per gigajoule and coal costs approximately 1 dollar to 4 dollars per gigajoule. Almost all internal combustion engines use liquid fuel. However a solid fuel can be suspended in a liquid to form an emulsion.
Coal particles can be suspended in water, methanol or ethanol. Water is cheaper than methanol or ethanol but it cools any flames and delays or extinguishes any combustion. Ethanol and methanol are adequate to use as fluid for suspension however they cost more than water. Most emulsions will be approximately 40-60 percent solids. Solids can include coal, wood, sugar cane, cellulose, hemicellulose, lignin and other suitable solids.
It is important to maintain temperatures to be hot enough in a combustion chamber to initiate combustion. For this reason maintaining heat in a combustion chamber is very important. Many scientists believe that relatively rapidly with little development effort it will be possible to create emulsions with particle size less than approximately 10 microns and suspend them in a water, methanol and ethanol mixture. The more water in the liquid portion in the mixture, the less it is necessary to use expensive ethanol or methanol. It will be important to have a rotating body that absorbs the heat of combustion during one combustion cycle and releases heat during the next combustion cycle. The design of two combustion chambers burning fuel with approximately 1% ash with complex valves is too complex a valve design to be economically viable, however, emulsion technology will advance relatively quickly. In a relatively short period of time it will be possible to burn a methanol, water and coal mixture with only one combustion chamber per compressed volume to create usable energy.
The ash will need to be ejected periodically at the end of the expansion gas phase or the beginning of the compression phase. The combustion chamber should have a spinning body in it with a large surface area. The spinning body helps rotate and mix the air and the surface area allows the air and fuel to heat up rapidly. One way that it can be done is with plurality of spinning blades that protrude from a central shaft. The spinning blades have a relatively large amount of surface area. The spinning blades may be turned to move the air forwards or backwards along the axis of rotation, or the thin plane of blades may be parallel with a long axis shaft. When gas explosions occur, gas can move from axial direction toward the discharge opening without creating a thrust force or counterforce along the axial line. This reduces thrust loads on the bearings.
Many fuels such as coal, wood and biofuel contain ash. These ash particles will act like an abrasive and create wear on the lubricated surface of an expander. Most engines will use a piston in a cylinder to expand the hot gas and produce energy. The piston must be kept sealed against the cylinder and requires a thin film of lubricant between the piston ring and cylinder. Alternatively, wankel engines use a wankel rotor with a rotor seal that slides against a rotary housing. When fuels with ash are directly burned in an expander, the ash can cause abrasion of the lubricated surface. Fuels with ash are not practical to burn in most engines since the ash will create wear of the lubricated surfaces of the expander. Prior designs have tried to overcome the relatively large amount of wear created by these abrasive particles.
It is an object of the present invention to provide to send compressed gas to an external combustion chamber where the hot combustion gas has ash removed before the gas returns to an expander to create energy. The ash is removed separately through an ash valve to an ash container.
It is an object of the present invention to prevent most of any ash present to avoid enter the expander and create wear on a lubricated surface. Fuel with water in it must vaporize the water before the water fuel mixture combusts. For example coal and water mixtures usually have higher ignition energy than gasoline. Hemicellulose lignin and cellulose mixed with water will need more ignition energy than gasoline. These fuels must burn fast enough to fully oxidize in short phase of maximum compression that typically occurs at top dead center of piston cycle especially at part loads.
It is the object of the present engine to design a combustion chamber that can absorb combustion energy from one combustion cycle and release it into the emulsion fuel mixture of the next combustion cycle. During combustion heat is absorbed onto the surface of rotating body. In the next combustion cycle the heat is released from the rotating surface into the emulsion fuel to initiate vaporization and combustion. The author of this invention is not aware of another internal combustion engine that uses a rotating body inside a combustor to store and then release heat into an emulsion fuel.
It is an object of the present invention to provide an engine that allows a phase of maximum compression to last over a complete 360 degrees of a crankshaft angle, keeping in mind that typical piston and wankel engines do not isolate the compressed gas from the compressor.
It is an object of the present invention to provide an engine that uses a valve between a combustion chamber and a compressor to seal gas in the combustion chamber. While the gas is in the combustion chamber for a relatively prolonged period of time combustion can be fully completed when the valve to expander opens and all heat has been added to the compressed air. This is in contrast to ordinary engine combustion that continues to proceed during a process of gas expansion.
It is anticipated that the effectiveness of the hot rotating body at facilitating combustion of emulsion fuels will lead to proliferation of emulsion fuel research.
As emulsion fuel research occurs lower ash emulsions will be developed that have less than 0.1 percent ash called ultralow ash. The ultralow ash fuel will can be burned in a single combustion chamber connected with a rotating body in the combustion chamber. The ultralow ash fuels that are emulsions can still contain water and would benefit from the hot rotating body in the combustion chamber. A object of this invention is to patent a hot rotating body in combustion chamber of engine that burns liquid solid emulsion that contain water.